OpenCvSharp函数:ContourArea、ArcLength、BoundingRect、MinAreaRect、BoxPoints
ContourArea计算轮廓面积//函数原型1doubleContourArea(InputArraycontour, booloriented=false)//函数原型2doubleContourArea(IEnumerablecontour, booloriented=false)//函数原型3doubleContourArea(IEnumerablecontour, boolorie